For any graph displayed in this system, you can:
 

• Click and hold the left mouse button.  Drag the mouse left, right, up or down to move the "paper" that the graph is drawn on.
• Click the "rocket ship" symbol on the graph to zoom out.  (This will give a fuller view of the graph.)
• Click the "knife" symbol on the graph, so that it turns black.  You can then click and drag a "zoom box" around any portion of the graph, to zoom in on that portion.
• Remember that you can always click "Reload" on your browser, to reset the mathematics to its original state.